This invention relates to aerodynamic propulsion devices and, in particular, to propulsion fans.
Typically, systems and methods for transferring power from an engine to a propulsion fan of an aircraft employ complicated mechanical linkages, such as bevel gears and mechanical transmission devices. Additionally, the systems and methods typically use some sort of clutch, mechanical or fluid, to engage and disengage the power transfer from the engine to the fan and to implement different gearing ratios.
Unfortunately, using mechanical linkages to transfer power from the engine to the propulsion fan introduces a variety of problems. For example, the mechanical linkages introduce power losses due to friction, slippage, and heat and reliability problems due to mechanical wear. Additionally, it is difficult to smoothly vary the amount of power delivered to the fan from the engine. Furthermore, it is difficult to power a single fan from multiple engines to provide redundancy, in case an engine were to fail. Moreover, it is difficult to shift a fan from a horizontal to a vertical application.
The present invention substantially reduces or eliminates at least some of the problems and disadvantages associated with previous systems and methods for driving propulsion fans. Accordingly, in particular embodiments, the present invention provides a propulsion fan that has a reduced number of mechanical linkages, a quick response to input commands, and redundancy capability.
An electromagnetic propulsion fan in accordance with certain embodiments of the present invention includes a hub and a plurality of fan blades coupled to the hub. The electromagnetic propulsion fan also includes a rim coupled to the fan blades such that rotating the rim causes the fan blades to rotate. The rim includes a plurality of magnets coupled thereto. The electromagnetic propulsion fan further includes a plurality of electromagnets in proximity to the rim, the electromagnets controllable to generate magnetic fields that interact with the magnetic fields of the magnets to cause the rim to rotate.
A method for controlling an electromagnetic propulsion fan in accordance with the present invention includes generating an instruction specifying the electrical power to be provided to a plurality of electromagnets and detecting a command regarding the rotational speed of a plurality of fan blades. The method also includes determining, if a command is detected, an adjustment to the specified electrical power to achieve the rotational speed of the command and generating a second instruction specifying the adjustment to the specified electrical power.
The present invention provides several technical advantages. For example, the present invention provides a propulsion fan that requires no mechanical linkages to transfer power between the driving elements and the driven elements. Thus, the propulsion fan is not as susceptible to mechanical wear and power loss due to mechanical interactions. Moreover, because no mechanical linkages are required to drive the propulsion fan, the driven elements may be readily engaged with and disengaged from the driving elements. As another example, the present invention provides a propulsion fan having the rotational speed controlled by supplied electrical power. Thus, the operations of the propulsion fan may be varied smoothly, continuously, and/or quickly. Furthermore, because electrical power may be readily varied by a variety of electronic devices, the rotational speed of the propulsion fan may be varied without varying the output from the electrical power generation device. Also because the rotational speed of the propulsion fan is controlled by supplied electrical power, the propulsion fan does not require a transmission to vary the rotational speed. Additionally, providing redundancy, by having the ability to provide the driving elements with electrical power from multiple sources, for example, is simplified. Moreover, it is possible to drive multiple fans from one power source without a complex transmission. As a further example, the present invention provides a propulsion fan that may be slowed and/or reversed without changing the motion of the driving elements or motors, which would likely be electrical generators. Thus, the operations of the propulsion fan may be controlled with a high degree of precision and flexibility. Note that some embodiments of the present invention may possess none, one, some, or all of these technical advantages and/or additional technical advantages.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, description, and claims.